The adjustment knob of a drag brake device provided in the rear portion of a conventional spinning reel of this kind has the drawbacks that since no fall-preventing member is provided, the adjustment member can drop off its screw portion when it is rotated in the direction in which the braking force is reduced, and since the rotation is continuous without any jumps, the knob can not be restricted and held at the drag brake adjustment position set by the angler.
To eliminate these problems, the provision of a fall-preventing mechanism for the adjustment knob, and resilient restriction of the rotation of the adjustment knob have been proposed in the past in patents such as U.S. Pat. Nos. 2,863,617, 3,074,664, 3,810,592, 4,238,085, and so forth. However, since these prior-art devices provide each of these mechanisms separately, the construction thereof is extremely complicated and difficult to assemble and a large space must be provided in order to incorporate the mechanisms.